Thin wall plastic tubing is often used for over-wrapping product containers, typically bottles, in which products, for example personal hygiene, pharmaceutical or food products, are shipped. In one form, the plastic tubing is applied as a label over a major portion of the container to identify the product and/or enhance the appearance of the container. In another form, the plastic tubing provides a tamper-evident band that covers the container cap and neck, serving to indicate whether the container has been opened after shipping. In many cases the plastic tubing is processed so as to be shrinkable by the application of heat after a cut length of tubing has been placed over the container, and thus the tubing conforms snugly to the contours of the container.
The subject plastic tubing labels and tamper-evident bands are applied to product containers in manufacturing environments, therefore process speed, tubing length consistency and neatness of the cut edge are important factors. Most known machines for the application of thin wall plastic tubing to containers employ a scissor-type double blade cutter or a guillotine-type single blade cutter. Another cutter type is described in U.S. Pat. No. 5,531,858 entitled “Shrinkable Label Inserting Machine” in which a plurality of blades are mounted circumferentially around a passage through which a thin wall plastic tube is conveyed. Each of the blades is mounted rotatably on a wheel that is in contact with a driven band, e.g. a belt or chain. When an appropriate length of tubing has moved through and extends beyond the passage, the band is rotated to cause the blades to swing in plural overlapping arcs, cutting the tubing. A drawback of the cutter described in the '858 patent is that for each cut to occur, the band and the plurality of wheels and blades must be driven from a stop to a high rotational speed in a minimal time interval. This rapid acceleration and subsequent deceleration requires a relatively large expenditure of energy and causes relatively great wear of machine components. A further drawback of the '858 patent cutter is that the mechanism is limited to a small range of tubing diameters, and the diameter of the cutter mounting circle as well as the number of cutters must be changed to accommodate a significantly different tubing diameter. The cutter invention disclosed below provides the needed speed, consistency and neat cut while minimizing the power requirement and amount of wear. Furthermore, the present invention cutter is capable of handling a greater range of tubing diameter than previously known without requiring equipment modification.